Ventilating moisture barrier for roof vent

ABSTRACT

The present invention relates to a protective barrier adapted to fit over a roof vent, particularly an off-ridge roof vent, which provides for ventilation and also restricts pass-through of wind-driven rainwater. The barrier comprises two parallel orifice plates, such as louvered panels with passages, that are spaced apart a desired distance by a stagnation zone, so that the device is effective to reduce or eliminate of passage of wind-driven rainwater to the interior of the vent. In various embodiments, the number of louvers in the more outward-disposed orifice plate is greater than the number of louvers in the more inward-disposed orifice plate.

FIELD OF THE INVENTION

The present invention relates to a protective barrier for a roof vent, particularly for an off-ridge roof vent. The barrier may be affixed to existing vents, pre-assembled onto, or integral with vents. The barrier comprises two parallel orifice plates, such as louvered panels, that are spaced apart a desired distance, so as to provide for ventilation and also to restrict pass-through of wind-driven rainwater.

BACKGROUND OF THE INVENTION

Roof ventilation devices of various designs have been incorporated into roofs and adjacent building structures, such as soffits, to provide for circulation to eliminate undesired heat build-up, such as in an attic. For example, during hot days air may flow through screened openings in soffits, into an attic space, and out of one or more roof ventilation devices. Roof ventilation devices may be powered, such as attic fans, or passive, such as roof vents. Two common classes of roof vents are ridge vents and off-ridge vents. Off-ridge roof vents, which are offset from the ridge of a roof, afford certain advantages as far as ease of installation, low cost and relatively low maintenance.

However, unprotected openings of roof vents may allow undesired entry of water into the house, such as into the attic, during extreme weather conditions. This has been appreciated and addressed in various manners. For example, U.S. Pat. No. 5,921,863, issued Jul. 13, 1999 to Gary L. Sells, discloses an arrangement of an inner and an outer plate to protect a ridge vent. The inner plate has parallel upwardly facing louvers, while the outer plate has an equal number of downwardly facing louvers. During normal wind conditions there are open passages through adjacently positioned louvers of the inner and outer plates, conducive to ventilation. Also, the outer plate is slidably arranged so as to be urged upward a distance due to high wind conditions. In such upward position, there is a closing of the passages between the inner and outer sets of louvers (see FIGS. 14-16 and accompanying disclosure). Although this approach involves a moving part, the disclosure does not indicate what maintenance is required to maintain the movable outer plate in a condition to appropriately respond by movement to a particular potentially deleterious wind speed. Other approaches to protect openings in ridge roof vents also are disclosed in this Sells patent.

Also, U.S. Pat. No. 5,797,222 to Paul Martin discloses a roof ridge and gable extension ventilation device that comprises a pair of spaced parallel upstanding sidewalls each comprising a plurality of vent openings, with interior return vent walls extending from the sidewalls, and comprising vent openings. The disclosure discloses that the latter vent openings, formed at louvered portions, are positioned above the corresponding louvers of the respective sidewalls. This is stated to be so oriented for assuring that the interior opening through the roof at the roof ridge, termed the roof vent, will stay dry.

Other references disclose various approaches to provide a form of protection for roof vents. These include U.S. Pat. No. 4,280,399, U.S. Pat. No. 4,588,637, U.S. Pat. No. 5,050,489, U.S. Pat. No. 5,535,558, and U.S. Pat. No. 6,554,700. U.S. Pat. No. 6,202,372 discloses a specific approach to an off-ridge roof vent having increased resistance to bending.

In tropical and semi-tropical regions, roof ventilation devices such as off-ridge roof vents are commonly provided to houses and other buildings to deal with high heat during the summers. Generally off-ridge roof vents have an elongated opening of low profile. However, many off-ridge roof vents were designed without full consideration of risks of water entry due to high-force wind, such as during a hurricane. Thus, despite the existence of various approaches to protect the entrances of roof vents, there continues to be a need for a protective barrier for off-ridge roof vents that is effective to reduce or eliminate water ingress during high speed wind and rain events such as hurricanes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A provides a cross-sectional view of one embodiment of a ventilating moisture barrier of the present invention as it is positioned in an exterior aperture of a roof vent. FIG. 1 B provides an enlargement of the moisture barrier of FIG. 1A to more clearly identify certain features. FIG. 1C provides a front view of the roof vent of FIG. 1A showing the opening into which the ventilating moisture barrier in FIG. 1A is positioned, however without depicting that barrier.

FIG. 2 provides a larger depiction of the cross-section view of the ventilating moisture barrier depicted in FIG. 1A, however not in association with the roof vent.

FIGS. 3A-C provide, respectively, front, transverse section, and cross-sectional side views of one embodiment of a first orifice plate component of the present invention.

FIGS. 4A-C provide, respectively, front, top, and cross-sectional side views of one embodiment of a second orifice plate component of the present invention.

FIGS. 5A provides a cross-sectional view of the assembled first orifice plate and second orifice plate components depicted in FIGS. 3A-4C. FIG. 5B provides a front view of two panels of the present invention disposed side-by-side to provide a span suitable to a common size of off-ridge roof vent aperture.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention comprises a ventilating moisture barrier for covering an exterior aperture of a roof vent, particularly of a standard-sized off-ridge roof vent. Embodiments include the barrier itself, and a roof vent comprising the barrier (whether as a kit for assembly or integral or pre-assembled as part of the roof vent). The present invention is designed to reduce or eliminate the passage of water, such as water in aerosol droplet form, through a roof vent and into a roof attic space during high-wind events such as hurricanes. This is achieved while retaining the basic capacity of the respective vent to operate to vent hot gases from an attic space during non high-wind conditions.

Embodiments of the ventilating moisture barrier of the present invention comprise three functional components in spaced relationship to one another. These are described below and illustrated by example through reference to the figures appended hereto.

In order to provide for an understanding of aspects of the present invention, FIG. 1A provides a cross-sectional view of one embodiment of a ventilating moisture barrier 100 of the present invention as it is positioned in an exterior aperture 60 of a prior art roof vent 50. The roof vent 50 as shown is installed in an inclined roof 55 (only partial section shown) depicted with an inclination angle of approximately 30 degrees, which is not meant to be limiting. The roof vent 50 comprises a top 56 (having an inflection 57 as shown), a front lip 58, two openings 65 covered by screen mesh 66, and an interior entrance 67 into an attic space 68. Also depicted are an exterior side 62 and an interior side 64 with respect to the exterior aperture 60.

The ventilating moisture barrier 100 of FIG. 1A covers the exterior aperture 60, and attaches to the front lip 58 by means of attachment through a top flange 102. The ventilating moisture barrier 100 attaches to a part of the roof and/or vent structure (i.e., a bottom plate typical of standard off-ridge roof vents) that is below a bottom flange 104, and may also attach to sides of the exterior aperture (e.g., see FIG. 1C).

FIG. 1B provides an enlarged cross-section depiction of the moisture barrier 100 of FIG. 1A to more clearly identify certain features. A first functional component of the ventilating moisture barrier 100 is a first orifice plate 110 that is disposed to face the exterior side 62 of the roof vent exterior aperture 60 (see FIG. 1A). The first orifice plate 110 is comprised of a flattened structural body 112 from which extend a first number of exterior louvers 114 that, as depicted in FIGS. 1A and 1 B, are disposed to angle downwardly to the exterior as one considers the declination from the top to the bottom of each exterior louver 114. Exterior passages 116 formed through the first orifice plate 110 interiorly to the respective exterior louvers 114 provide for passage of air.

A second functional component of the ventilating moisture barrier 100 is a second orifice plate 120. The second orifice plate 120 is comprised of a flattened structural body 124 from which extend a second number of interior louvers 126 that, as depicted in FIGS. 1A and 1B, are disposed to angle downwardly and inwardly (with respect to the roof vent) as one considers the declination from the top to the bottom of each interior louver 126. In operational position, the second orifice plate 120 is interior to the first orifice plate 110, and is disposed to the interior side 64 of the roof vent exterior aperture 60 (see FIG. 1A). Interior passages 128 formed through the second orifice plate 120 interiorly to (with regard to the moisture barrier 100) the respective interior louvers 126 provide for passage of air.

As shown in FIGS. 1A and 1B, the second number, of interior louvers 126 is six, which is one less than the first number, of exterior louvers 114, seven. More generally, the second number of louvers (i.e., the number of louvers of the more interior, second orifice plate) is any number that is less than the first number of louvers of the more exterior, first orifice plate. Even more generally, when designs other than louvers (with a corresponding passage below a respective louver) are employed to provide ventilation through the first and/or the second orifice plates, the number of passages in the more exterior, first orifice plate is at least one greater than the number of passages in the more interior, second orifice plate. Also, as shown in the appended figures, the respective passages of the interior and exterior orifice plates are designed to provide for a relatively high percentage of open area, and in such embodiments the total open area of the passages of the second orifice plate, although there are fewer passages, is greater than the total open area of the first orifice plate's passages. Consequently in such embodiments the second, interior orifice plate's passages are proportionally larger on an individual, per passage basis. However, this is not meant to be limiting of the scope of the claims appended hereto.

A third functional component of the ventilating moisture barrier 100 is a stagnation zone 130 disposed between the first orifice plate 110 and the second orifice plate 120. The stagnation zone 130 has a defined depth, identified in FIG. 1B by 140. In some embodiments the defined depth 140 is at least the depth 160 of the louvers 126 of the second orifice plate (this depth shown as 160 in FIG. 1B, measured horizontally from a first end 161 to a second end 162). In some embodiments, the defined depth 140 of the stagnation zone 130 between the first orifice plate and the second orifice plate is at least 1.25 times the depth 160 of the louvers 126 of the second orifice plate 120, or, alternatively, is at least 1.50 times the depth 160 of the louvers 126 of the second orifice plate 120. More generally, the distance 140 may be a defined depth sufficient to be effective to reduce passage of wind-driven rainwater through the passages 128 of the second orifice plate 120. More particularly, the depth 140 may be established to be effective to reduce, or to eliminate, passage of wind-driven rainwater beyond the second ends 162 of louvers 126, when positioned in a roof vent as disclosed herein.

FIG. 1C provides a front perspective view of the prior art roof vent 50 of FIG. 1A installed onto roof 50, however, without the ventilating moisture barrier affixed, in order to clearly show certain features. A bottom plate 52 supports side panels 54 and the top 56, which comprises inflection 57. The front end of top 56 meets a front lip 58, which is positioned above the exterior aperture 60. FIG. 1C illustrates that the exterior aperture 60 is defined peripherally by the front lip 58, a left side 80 and a right side 82, and a bottom delineation 84 that extends transversely to form a line between a bottom point 81 of the left side 80 and a bottom point 83 of the right side 82. In various applications, embodiments of the present invention are affixed to such elements; also, the bottom flange (see FIG. 1A, component 104) may attach to a part of the roof and/or vent structure (i.e., a bottom plate typical of standard off-ridge roof vents) that is adjacent and down the roof from the bottom delineation 84.

While not meant to be limiting, the ventilating moisture barrier 100 in FIG. 1B shows a bottom flange 104 in which the attachment surface 105 is extended downward from the remainder of the bottom flange 104, resulting in a gap 107 between most of the bottom flange 104 and the roof (not shown). This provides for drainage of rainwater. It is appreciated that various arrangements for attachment to a particular roof vent may be utilized in various embodiments (such as without the use of top and bottom flanges). Also, it is appreciated that for differing styles of roof vent openings, an additional section of extruded aluminum, or other linear material, may be utilized to fill a space between a part of that opening and a protective moisture barrier embodiment. Such additional sections may be provided in a kit to ensure that a particular embodiment of a protective moisture barrier may be readily adapted to fit onto a variety of roof vent openings.

FIG. 2 provides the same cross-section view of the embodiment 100 depicted in FIG. 1A, however not in association with the roof vent 50 and additionally showing certain expected aspects of wind velocity and moisture during high-wind conditions. Without being bound to a particular theory, the embodiment 100 is believed to provide reduction or elimination of entry of wind-driven rainwater by the following sequence of events within the three stated components, due to their design and juxtaposition. For example, consider a wind force of 100 miles per hour (“m.p.h.”) during a hurricane, carrying rainwater toward the first orifice plate along the vector “A”. Apart from a certain resistance due to the total of frictional losses and other resistance in the path to an exit (i.e., screened apertures in a soffit of the roof, convection forces of warm air rising through the attic, etc.), due to the barrier effect of the first orifice plate 110 (i.e., the decrease in open area compared to no obstruction, due largely to the surface area of the flattened structural body 112), the velocity of the wind is expected to fall to substantially lower than 100 m.p.h. as it crosses the stagnation zone 130. That is, the wind velocity at point B is substantially lower than the wind velocity at the location of vector point “A”. This is believed to result in a substantial tendency of wind-borne water aerosol droplets to drop from the predominantly horizontal travel direction. Some such droplets 260 may, as a result of the drop in wind velocity, fall toward or to a roof portion 250 below the stagnation zone 130, and thereafter flow by gravity downward and out of the vent exterior aperture (not shown in FIG. 2).

Water still entrained in the now-decreased-velocity wind may alternatively encounter the louvers 126 of the second orifice plate 120, and thereon collect, coalesce, and drop sequentially along such louvers 126 until reaching the roof (not shown). The wind passing through the second orifice plate 120 is expected to experience a further decrease in velocity due to the restricted open area based on the surface area of the flattened structural body 124, followed by a larger volume farther inward. However, while the design is effective to reduce the inflow of wind-driven rainwater, particularly during high wind conditions such as during a tropical storm or hurricane, the respective open areas of openings (represented by exterior passages 116 and interior passages 128 in FIGS. 1A, 1B and 2) are sufficient to provide for inflow and outflow of air during normal wind conditions, and thereby to provide for effective ventilation of the attic space through the roof vent.

Other aspects of the juxtaposition of the louvers and the passages of the first and the second orifice plates are relevant to various embodiments of the invention. First, for various embodiments at least one of the interior louvers is aligned laterally with one of the exterior louvers. By “aligned laterally” is meant that at least one interior louver is positioned vertically within the range of elevations defined between the highest and the lowest of the exterior louvers. In various embodiments, at least half of the interior louvers are aligned laterally with exterior louvers. This provides for efficient airflow under low velocity conditions, such as during normal (non-storm wind speed) ventilation conditions. Further, it is appreciated that for the embodiment depicted in FIGS. 1A, 1B and 2, all of the interior louvers 126 are entirely disposed between the highest exterior louver 114H and the lowest exterior louver 114L, as indicated by dashed lines 280 and 282). It is noted that the designed angle of installation is established by the structures used for attachment to a roof vent, and may be secondarily affected by a particular inclination of a roof upon which a roof vent is installed. In most cases, the designed angle of installation is between about 0 degrees (i.e., vertical) and about 30 degrees from the vertical.

Similarly, it is appreciated that for various embodiments at least one of the interior passages is aligned laterally with one of the exterior passages. By this is meant that, when a barrier of the present invention is at the installed angle, extending a horizontal line from the lowest point of the lowest exterior passage and from the highest point of the highest exterior passage inward to the interior passages, at least one interior passage is between such lines. Also, it is appreciated that the term “passages” in this paragraph may refer to any opening suitable for passage of air through the respective orifice plate, whether or not a louver is associated with it.

It also is appreciated that for various embodiments the first and the second orifice plates, although spaced apart by the stagnation zone, are substantially parallel to one another rather than disposed angularly. By substantially parallel is meant that there is no more than about a 15 degree angle of inclination of one such plate toward or away from the other.

Embodiments of the present invention may be formed from materials such as plastics, such as by injection molding, and metals, such as by various methods of fabrication as known in the art, including but not limited to form rolling and stamping. With regard to plastics types, ABS, polypropylene, and polypropylene with talc as a filler, may be utilized, as well as any other type of thermoplastic known to those skilled in the art. Generally and as desired based on design criteria, weepage openings may be included on downwardly facing bottom portions or edges to permit any collected liquids to drain therethrough. Also, struts, ribs, and other supports, and tabs through which fastening means (nails, screws, rivets, etc.) may be used for affixing the barrier to the vent or roof, may be incorporated in various embodiments although not depicted explicitly in the figures.

EXAMPLE 1

One approach to fabrication and assembly is exemplified in FIGS. 3A-C, 4A-C, and 5A. These are not meant to be limiting.

FIGS. 3A-C provide, respectively, front, transverse section, and cross-sectional side views of one embodiment of a first orifice plate panel 300 of the present invention, for assembly with a second orifice plate panel 400 as depicted in FIGS. 4A-C. Viewable in FIG. 3A are a structural body 302 and six sections 304 of louvers 306 that extend transversely (i.e., from left to right) and extend above like-disposed passages 307 (see FIG. 3C). The structural body 302 further is comprised of end sections 308, transverse ribs 310 between adjacent louvers 306 of a respective section 304, and vertically arranged structural major members 312 and lesser members 314 separating adjacent sections 304. It is noted that the end sections 308 at opposite left and right ends are molded offset to one another so as to provide a lap-type joining when a left side of one panel 300 is overlapped with a right side of a second panel 300. Lower attachment members 316 disposed along bottom flange 317 provide openings 318 for insertion of screws, nails, or other attachment means (not shown) to secure the first orifice plate panel 300 to the roof and/or a plate of the roof vent (not shown). Along top flange 321 are provided openings 322 for insertion of screws, nails, or other attachment means (not shown) to secure the first orifice plate panel 300 to a front surface of the roof vent (not shown, see FIGS. 1A and 1C). The presence of such openings is not meant to be limiting, as the surfaces of the top flange 321 and the bottom flange 317 may be utilized for attachment, such as by driving a screw through such surfaces.

FIG. 3B provides a transverse sectional downward view of the taken along the B-B plane of FIG. 3A. This view illustrates seven spaced apart vertical ribs 330 (depicted as dashed lines in FIG. 3A), four of which comprise enlarged areas 332, comprising holes 334. The holes 334 are sized to receive screws for assembly of the first orifice plate 300 with the second orifice plate 400. More generally, this is not meant to be limiting as any of a variety of approaches to joining, or to juxtaposing, the first and second orifice plates may be utilized, so as to obtain a desired stagnation zone therebetween.

FIG. 3C provides a cross-sectional view taken along the B-B line of FIG. 3A. This view is essentially identical to that view of the corresponding component depicted in FIG. 2.

FIGS. 4A-C provide, respectively, front, top, and cross-sectional side views of one embodiment of a second orifice plate panel 400 of the present invention, for assembly with the first orifice plate panel 300 as depicted in FIGS. 3A-C. The structural and functional components of the second orifice plate panel 400 have similarities to those of the first orifice plate panel 300 of FIGS. 3A-3C. Viewable in FIG. 4A are a structural body 402 and six sections 404 of louvers 406 that extend transversely (i.e., from left to right) and extend above like-disposed passages 407 (see FIG. 4C). The structural body 402 further is comprised of end sections 408, transverse ribs 410 between adjacent louvers 406 of a respective section 404, and vertically arranged structural major members 412 and lesser members 414 separating adjacent sections 404.

FIG. 4B provides a top view of the second orifice plate panel 400 of FIG. 4A. Viewable is an upper bridging member 425, that extends across the top of the stagnation zone (not shown, see above) once assembled. Generally, the presence of an upper bridging member is not meant to be limiting as to all embodiments, as elements other than those disclosed in this example may be utilized to span the stagnation zone and separate the first and second orifice plates.

FIG. 4C provides a cross-sectional view taken along the C-C line of FIG. 4A. The upper bridging member 425 is sized to abut the first orifice plate (not shown in FIG. 4A) at a point above the joining of the topmost louver of the first orifice plate with its flattened structural body (not shown in FIG. 4A, see FIGS. 1A and 2). This view is essentially identical to that view of the corresponding component depicted in FIG. 2.

The first orifice plate panel 300 and the second orifice plate panel 400 of Example 1 fit together to form a unit 500 of a ventilating moisture barrier of the present invention. A cross-section of one such unit 500 is shown in FIG. 5A. Also apparent in FIG. 5A are the upper flange 502 and the lower flange 504, respectively above and below the areas of louvers and passages.

Two such units 500 are shown side-by-side in FIG. 5B. It is noted that an aperture of a standard off-ridge roof vent has a width of about 46.5 inches, so that such two panels 500 may each have a width of about 23.3 inches and thereby be appropriately sized to cover one such standard off-ridge vent exterior aperture (not shown in FIG. 5B). When placing or joining two such units is such side-by-side arrangement, the two units may be joined together, such as by a lap-type junction provided by the offset nature of the end sections 308 of first orifice plate panels 300 (see FIG. 3A). Alternatively, embodiments of the present invention may be joined together by a butt junction, or by other joining designs known to those skilled in the art.

Table 1 summarizes dimensions of the combined, side-by-side use of two units 500 to cover an aperture of a standard off-ridge roof vent having a width of about 46.5 inches. These dimensions are meant to be illustrative but not limiting. TABLE 1 Distance a 46.3 inches Distance b 23.3 inches Distance c 4.925 inches Distance d 4.419 inches Angle e 45 degrees

Although the aperture of most off-ridge roof vents has a width of about 46.5 inches, such width is not meant to be limiting. Accordingly, it is appreciated that a unit of a ventilating moisture barrier of the present invention may be made to have a particular width that is a fraction of a desired aperture width. Then a desired number of such units may be used to cover any of a number of roof vents having widths that are multiples of such particular width.

Also, it is appreciated that various other forms of construction, including fabricating an integral structure comprising the first exterior and the second interior orifice plates, may be done and would be within the scope of the present invention.

It is appreciated that the angling of the louvers need not be as shown in FIG. 1A and other figures above. For example, not to be limiting, the angling could be reversed, so that louvers of the first orifice plate angle inward from the exterior to the interior. However, although such orientation may promote downward movement and loss of water from the air current, this orientation also could lead to greater accumulation of debris, such as tree leaves and the like, within the ventilating moisture barrier. (It is noted that such may be prevented, at least to some extent, by providing a screen cover, which may, however, require greater maintenance that the embodiment depicted in FIG. 1A.)

While the above embodiments and disclosure are directed to a protective moisture barrier for an off-ridge roof vent, it is appreciated that the present invention also may be utilized for other types of roof vents. For example, not to be limiting, the present invention may be employed to cover the outer apertures of ridge roof vents.

In summary, through disclosure of the aspects of embodiments of the present invention, it is apparent that the present invention provides for high levels of ventilating airflow during normal conditions of operation of a roof vent, so as to not impair ventilation efficiency. Additionally, the present invention provides for reduction of passage of wind-driven rainwater during high wind conditions such as are associated with tropical storms and hurricanes. Consequently, the present invention advances the art of ventilating moisture barrier protective covering devices for roof vents, particularly for off-ridge roof vents.

Embodiments of the present invention may be in any of the following forms: a ventilating moisture barrier, as a single unit or two or more units that together cover an exterior aperture of an existing roof vent; and a roof vent in combination with a ventilating moisture barrier, whether these are integrally formed, pre-assembled, or assembled during the installation process of the vent. Kits may also be provided comprising the components of an embodiment of a ventilating moisture barrier of the present invention, and also including screws or the like for assembly and installation, and instructions for assembly and installation. Additional components may be supplied to provide for installation on a variety of roof vent openings. More generally, assembly of an embodiment of a ventilating moisture barrier, or installation of the same to cover a roof vent exterior aperture, may be done using any means for attachment known to those skilled in the art, which may include: thermoplastic welding; sonic welding; welding; gluing or other adhesion by an adhesive, such as but not limited to caulk; screws; nails; rivets; staples; magnets; hooks; clamps; lugs; pins; or other mechanical linking or couplings, any type of fastener, any type of connector, or any other suitable conventional attachment mechanism, system or device. Surfaces of the embodiments of the present invention may provide for, or may comprise, holes or slots, that provide for attachment by such means for attachment.

All patents, patent applications, patent publications, and other publications referenced herein are hereby incorporated by reference in this application in order to more fully describe the state of the art to which the present invention pertains, to provide such teachings as are generally known to those skilled in the art, and, with regard to standard features and/or components common to embodiments of those references and the present disclosure, to provide teachings specific to embodiments of the present invention that utilize combinations of features that include one or more such features and/or such components described in the referenced patent applications.

While certain embodiments of the present invention have been shown and described herein in the present context, such embodiments are provided by way of example only, and not of limitation. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the invention herein. For example, the present invention need not be limited to best mode disclosed herein, since other applications can equally benefit from the teachings of the present invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims. 

1. A ventilating moisture barrier for covering a roof vent exterior aperture, the roof vent exterior aperture having a height and a width defined respectively by distances between a front lip and a bottom delineation, and a left side transversely spaced from a right side, the ventilating moisture barrier comprising: a. a first, exterior orifice plate comprising a first number of exterior louvers extending transversely, and a plurality of exterior passages formed through the first orifice plate; b. a second, interior orifice plate comprising a second number of interior louvers extending transversely, and a plurality of interior passages formed through the second orifice plate; and c. a stagnation zone disposed and establishing a distance between the first orifice plate and the second orifice plate, the distance effective to reduce passage of wind-driven water droplets through the interior passages; wherein the first number is greater than the second number, and wherein at least one of the exterior louvers is aligned laterally with one of the interior louvers.
 2. The ventilating moisture barrier of claim 1, additionally comprising a top flange and a bottom flange providing respective surface or holes for means for attachment, respectively, to the top lip and a portion of roof below the bottom delineation.
 3. The ventilating moisture barrier of claim 1, wherein at least half of the exterior louvers is aligned laterally with the interior louvers.
 4. The ventilating moisture barrier of claim 2, the interior louvers having a lateral depth measured between a first end and a second end, wherein the stagnation zone distance is at least the lateral width.
 5. The ventilating moisture barrier of claim 4, wherein the stagnation zone distance is at least 1.50 times the lateral width.
 6. The ventilating moisture barrier of claim 1, the interior passages providing a first total open area greater than a second total open area of the exterior passages.
 7. The ventilating moisture barrier of claim 2, wherein the first number is seven and the second number is six.
 8. A ventilating moisture barrier comprising a. a first orifice plate comprising a first number of interior louvers extending transversely, and a plurality of passages formed through the first orifice plate; b. a second orifice plate comprising a second number of exterior louvers extending transversely, the exterior louvers having a depth from a first end to a second end, and a plurality of passages formed through the second orifice plate; and c. a stagnation zone between the first orifice plate and the second orifice plate, establishing a distance effective to reduce passage of wind-driven water droplets through the second orifice passages; wherein the first number is greater than the second number, and wherein the first orifice plate and the second orifice plate are positioned substantially parallel.
 9. The ventilating moisture barrier of claim 8, additionally comprising a top flange and a bottom flange providing respective surface or holes for means for attachment.
 10. The ventilating moisture barrier of claim 8, wherein at least half of the exterior louvers is aligned laterally with the interior louvers.
 11. The ventilating moisture barrier of claim 8, the interior louvers having a lateral depth measured between a first end and a second end, wherein the stagnation zone distance is at least the lateral width.
 12. The ventilating moisture barrier of claim 11, wherein the stagnation zone distance is at least 1.50 times the lateral width.
 13. The ventilating moisture barrier of claim 11, the plurality of passages formed through the second orifice plate providing a first total open area greater than a second total open area of the plurality of passages formed through the first orifice plate.
 14. The ventilating moisture barrier of claim 11, wherein the first number is seven and the second number is six.
 15. A roof vent comprising a bottom plate, a top surface, and side panels, and an exterior aperture having a height and a width defined respectively by distances between a front lip and a bottom delineation, and a left side transversely spaced from a right side, and a ventilating moisture barrier covering the exterior aperture, the ventilating moisture barrier comprising: a. a first orifice plate comprising a first number of exterior louvers extending transversely, and a plurality of passages formed through the first orifice plate; b. a second orifice plate comprising a second number of interior louvers extending transversely, the interior louvers having a depth from a first end to a second end, and a plurality of passages formed through the second orifice plate; and c. a stagnation zone between the first orifice plate and the second orifice plate, establishing a distance effective to reduce passage of wind-driven water droplets through the second orifice passages; and wherein the first number is greater than the second number, and wherein the first orifice plate and the second orifice plate are positioned substantially parallel.
 16. The roof vent of claim 15, wherein at least half of the exterior louvers is aligned laterally with the interior louvers.
 17. The roof vent of claim 15, the ventilating moisture barrier additionally comprising a top flange and a bottom flange providing respective surface or holes for means for attachment to, respectively, the front lip and a portion of bottom plate along the bottom delineation.
 18. The roof vent of claim 15, the interior louvers having a lateral depth measured between a first end and a second end, wherein the stagnation zone distance is at least the lateral width.
 19. The roof vent of claim 15, the plurality of passages formed through the second orifice plate providing a first total open area greater than a second total open area of the plurality of passages formed through the first orifice plate.
 20. The roof vent of claim 15, wherein the first number is seven and the second number is six. 